| 摘要 |
PROBLEM TO BE SOLVED: To reduce the weight and enhance the rigidity by halving a horizontally columnar body along a cut line moving in parallel from the front end surface toward the rear end surface so that the cut surface has a plate piece having a continued surface consisting of the combination of hyperbolic paraboloids. SOLUTION: When the cutting of a horizontally columnar body 1 having a square section is performed from cut line 1, 3 to 6, 8 while it is equally halved along a cut line moving parallel from the front ends 1-4 toward the rear ends 5-8, and it is at that time rotated to the left at a rotating angle speed proportional to the advancing speed by a rotating angle 90 deg. along central axes 9, 10 passing the centers of gravity of the front end surface and the rear end surface, a basic form L of the cut surface 1, 3, 8, 6 is provided. When it is rotated to the right, a basic form R of cut surface 13, 15, 18, 16 symmetric to the above is provided. The cut line 1, 3 or 13, 15 has the same ratio of rotating speed to advancing speed, and the resulting cut surfaces 1, 3, 8, 6 and 13, 15, 18, 16 are hyperbolic paraboloidal. Accordingly, a light-weighted structural panel with high rigidity can be formed.
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